As the size of semiconductor devices has continued to shrink and circuit densities have increased accordingly, thermal management of these devices has become more challenging. In the past, thermal management in semiconductor devices was often addressed through the use of forced convective air cooling, either alone or in conjunction with various heat sink devices, and was accomplished through the use of fans. However, fan-based cooling systems are undesirable due to the noise attendant to their use. Moreover, the use of fans requires relatively large moving parts, and corresponding high power inputs, in order to achieve the desired level of heat transfer. Furthermore, while fans are adequate for providing global movement of air over electronic devices, they generally provide insufficient localized cooling to provide adequate heat dissipation for the hot spots that typically exist in semiconductor devices and in many types of electronic equipment.
More recently, thermal management systems have been developed which utilize synthetic jet ejectors. These systems are more energy efficient than comparable fan-based systems, and also offer reduced levels of noise and electromagnetic interference. Systems of this type are described in greater detail, for example, in U.S. Pat. No. 6,588,497 (Glezer et al.). The use of synthetic jet ejectors has proven very efficient in providing localized heat dissipation, and hence can be used to address hot spots in semiconductor devices and electronic equipment. Synthetic jet ejectors may be used in conjunction with fan-based systems to provide thermal management systems that afford both global and localized heat dissipation.
Despite their notable advantages, there is a need in the art for further improvements in synthetic jet ejectors. In particular, there is a need in the art for synthetic jet ejectors which have a reduced audible footprint. This need is especially great in hand-held devices such as cell phones, where the audible footprint of the thermal management system may detract from the usage of the device. At the same time, such applications require that the synthetic jet ejectors have a low profile and consume a relatively small amount of space. These and other needs may be met by the systems and methodologies disclosed herein.